Hostname: page-component-7bb8b95d7b-dvmhs Total loading time: 0 Render date: 2024-09-26T18:58:39.279Z Has data issue: false hasContentIssue false

The ventilated filling box containing a vertically distributed source of buoyancy

Published online by Cambridge University Press:  10 February 2010

PAUL COOPER*
Affiliation:
School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
GARY R. HUNT
Affiliation:
Department of Civil and Environmental Engineering, Imperial College London, Imperial College Road, London SW7 2AZ, UK
*
Email address for correspondence: pcooper@uow.edu.au

Abstract

This paper describes the fluid mechanics within a box containing a vertical plane distributed source of buoyancy. A theoretical analysis is presented that models the development of plumes from such sources in an unconfined ambient of uniform density. Two extensions are considered. The first concerns a sealed box and the second involves the more general situation where the box is ventilated by openings at top and bottom. In the sealed box the stratification develops in much the same way as for a ‘filling box’ containing a single-point source of buoyancy on the floor. An initial front descends from the ceiling of the box and an asymptotic stratification eventually develops which is continuous in the vertical direction. In the case of the ventilated box it is found that a complex stratification develops where one or more horizontal intrusions are formed by detachment of the plume/boundary layer from the vertically distributed source where the buoyancy of the plume is less than, or equal to, that of the stratified ambient at a given height. Experimental results are presented to demonstrate the validity of the theory. The findings are relevant to both forced and naturally ventilated buildings containing non-adiabatic vertical surfaces.

Type
Papers
Copyright
Copyright © Cambridge University Press 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Baines, P. G. 2002 Two dimensional plumes in stratified environments. J. Fluid Mech. 471, 315337.CrossRefGoogle Scholar
Baines, W. D. & Turner, J. S. 1969 Turbulent buoyant convection from a source in a confined region. J. Fluid Mech. 37, 5180.CrossRefGoogle Scholar
Bloomfield, L. J. & Kerr, R. C. 1998 Turbulent fountains in a stratified fluid. J. Fluid Mech. 358, 335356.CrossRefGoogle Scholar
Bolster, D. & Caulfield, C. P. 2008 Transients in natural ventilation – a time-periodically varying source. Build. Serv. Engng Res. Technol. 29, 119135.CrossRefGoogle Scholar
Chen, Z. D., Li, Y. & Mahoney, J. 2001 Natural ventilation in an enclosure induced by a heat source distributed uniformly over a vertical wall. Build. Environ. 36, 493501.CrossRefGoogle Scholar
Cooper, P. & Linden, P. F. 1996 Natural ventilation of an enclosure containing two buoyancy sources. J. Fluid Mech. 311, 153176.CrossRefGoogle Scholar
Dalziel, S. B. 1993 Rayleigh–Taylor instability: experiments with image analysis. Dyn. Atmos. Oceans 20, 127153.CrossRefGoogle Scholar
Germeles, A. E. 1975 Forced plumes and mixing of liquids in tanks. J. Fluid Mech. 71, 601623.CrossRefGoogle Scholar
Kaye, N. B. & Hunt, G. R. 2007 Overturning in a filling box. J. Fluid Mech. 576, 297323.CrossRefGoogle Scholar
Kumagai, M. 1984 Turbulent buoyant convection from a source in a confined two-layered region. J. Fluid Mech. 147, 105131.CrossRefGoogle Scholar
Leppinen, D. M. 1997 Aspects of convection. PhD thesis, DAMTP, University of Cambridge.Google Scholar
Linden, P. F. 1999 The fluid mechanics of natural ventilation. Annu. Rev. Fluid Mech. 31, 201238.CrossRefGoogle Scholar
Linden, P. F. & Cooper, P. 1996 Multiple sources of buoyancy in a naturally ventilated enclosure. J. Fluid Mech. 311, 177192.CrossRefGoogle Scholar
Linden, P. F., Lane-Serff, G. F. & Smeed, D. A. 1990 Emptying filling boxes, the fluid mechanics of natural ventilation. J. Fluid Mech. 212, 309335.CrossRefGoogle Scholar
McDougall, T. J. 1978 Bubble plumes in stratified environments. J. Fluid Mech. 85, 655672.CrossRefGoogle Scholar
Morton, B. R., Taylor, G. I. & Turner, J. S. 1956 Turbulent gravitational convection from maintained and instantaneous sources. Proc. R. Soc. Lond. A 234, 123.Google Scholar
Sandberg, M. & Lindstrom, S. 1987 A model for ventilation by displacement. In Proceedings of Roomvent 87: First Intl Conf. on Air Distribution in Rooms, Stockholm, Sweden.Google Scholar
Vliet, G. C. & Liu, C. K. 1969 An experimental study of turbulent natural convection boundary layers. ASME J. Heat Transfer 91, 517531.CrossRefGoogle Scholar
Wells, M. G., Griffiths, R. W. & Turner, J. S. 1999 Competition between distributed and localized buoyancy fluxes in a confined volume. J. Fluid Mech. 391, 319366.CrossRefGoogle Scholar
Worster, M. G. & Huppert, H. E. 1983 Time-dependent density profiles in a filling box. J. Fluid Mech. 132, 457466.CrossRefGoogle Scholar